Developing efficient and stable zeolites for vapor-phase Beckmann rearrangement of cyclohexanone oxime is still a great challenge to realizeε-caprolactam(CPL)green production.In this work,the hierarchical porous sili...Developing efficient and stable zeolites for vapor-phase Beckmann rearrangement of cyclohexanone oxime is still a great challenge to realizeε-caprolactam(CPL)green production.In this work,the hierarchical porous silicalite-1 zeolites with multiple hollow structure(S-1-M)are explored by in-situ desilication−recrystallization post-treatment of spongy highway-like zeolites(S-1-S),which are synthesized through silanization synthesis of conventional bulky silicalite-1(S-1).Compared to S-1,S-1-M achieves superior catalytic performance,with improving the CPL selectivity from 85.7%to 94.1%and prolonging the catalyst lifetime from 74 to 126 h at a weight hourly space velocity(WHSV)of 6 h^(−1).Comprehensive physiochemical studies demonstrate that the highly dispersed intracrystalline cavities within S-1-M endow greater mass diffusion and better quasi acidity inducing by the enhanced H-bonds among abundant H-bonded silanols,which is cooperatively responsible for its superior catalytic performance.展开更多
The addition of platinum over the B2O3/TiO2-ZrO2 remarkably enhanced its catalytic stability in the vapor phase Beckmann rearrangement of cyclohexanone oxime under the carder gas of H2. The content of coke deposited ...The addition of platinum over the B2O3/TiO2-ZrO2 remarkably enhanced its catalytic stability in the vapor phase Beckmann rearrangement of cyclohexanone oxime under the carder gas of H2. The content of coke deposited on catalyst surface was decreased from 1.92% over the B2O3/TiO2-ZrO2 to 1.14% over the platinum promoted B2O3/TiO2-ZrO2 after reaction of six hours. This result indicates that the platinum added on the B2O3/TiO2-ZrO2 catalyst plays an important role in reducing the coke formation on the catalyst surface.展开更多
Under mild conditions, conversion of a variety of ketoximes and aldoximes to their corresponding amides and nitriles proceeded in the presence of PEG-SO3H with high yields.
Six Brnsted acidic ionic liquids（ILs） 1a―1f were synthesized and used as the dual solvent-catalyst systems for Beckmann rearrangement reactions. Among ILs 1a―1f, IL 1a exhibited the highest catalytic activity and ...Six Brnsted acidic ionic liquids（ILs） 1a―1f were synthesized and used as the dual solvent-catalyst systems for Beckmann rearrangement reactions. Among ILs 1a―1f, IL 1a exhibited the highest catalytic activity and successfully catalyzed the Beckmann rearrangement of ketoximes, and the corresponding amides were obtained in good to excellent yields（74%―92%）. In addition, IL 1a could be recovered easily and reused at least three times without any loss of catalytic activity.展开更多
Deoxo 6 deoxy 6,9 epoxy 9,9 a didehydro 9 a aza 9 a homoerythromycin A (1), 9 deoxo 11 deoxy 9,11 epoxy 9,9 a didehydro 9 a aza 9 a homoerythromycin A (2) and 9 a aza 9 a ...Deoxo 6 deoxy 6,9 epoxy 9,9 a didehydro 9 a aza 9 a homoerythromycin A (1), 9 deoxo 11 deoxy 9,11 epoxy 9,9 a didehydro 9 a aza 9 a homoerythromycin A (2) and 9 a aza 9 a homoerythromycin cyclic lactam (3) were synthesized by the Beckmann rearrangement of erythromycin A 9 (E) oxime (4). The structures of compounds (1), (2) and (3) have been identified by their spectral data. The reaction mechanism was also discussed. The yield of the Beckmann rearrangement of compounds (4) was better than that reported in literatures.展开更多
Beckmann rearrangement mechanism of cyclohexanone oxime, based on the characteristic of self-catalyzed reaction and polymorphism was proposed. According to the suggested mechanism, the basic approach was the rearrange...Beckmann rearrangement mechanism of cyclohexanone oxime, based on the characteristic of self-catalyzed reaction and polymorphism was proposed. According to the suggested mechanism, the basic approach was the rearrangement of OXH+ while the SO3 acts as dehydrating agent and OXSO3 can turn to CPLSO3 ultimately. Considering self-catalyzed reaction between OXSO3 and CPLH+, kinetic model for Beckmann rearrangement was established. Corresponding parameters were estimated by using float genetic algorithm （GA） and simulation results agree well with the experimental data below -19.3℃. Industrial equipment was simulated and analyzed. Effects of key process parameters such as molar ratio of sulfuric acid to oxime and circulation ratio on the residual oxime are also discussed. The results show that the caprolactam exists as CPLH+ finally in oleum and the minimum molecular ratio of sulfuric acid to oxime can be 0.5 theoretically.展开更多
The Beckmann rearrangement of cyclohexanone oxime was achieved by the combined use of cobalt salt and Lewis acids co-catalysts (each 10 mol%). Various combinations of cobalt salts and Lewis acids gave lactams in a sat...The Beckmann rearrangement of cyclohexanone oxime was achieved by the combined use of cobalt salt and Lewis acids co-catalysts (each 10 mol%). Various combinations of cobalt salts and Lewis acids gave lactams in a satisfactory yield under mild conditions. This method makes it possible to reduce undesirable byproducts.展开更多
Beckmann rearrangements of oximes to lactams often require harsh conditions and/or the use of large amounts of acid catalyst. To reduce the amount of Bronsted acid required, and to avoid the formation of a large amoun...Beckmann rearrangements of oximes to lactams often require harsh conditions and/or the use of large amounts of acid catalyst. To reduce the amount of Bronsted acid required, and to avoid the formation of a large amount of undesirable byproducts under mild reaction conditions, a low environmental load process was developed. Beckmann rearrangements of cyclohexanone oxime and cyclooctanone oxime were achieved using a combination of a Bronsted acid and cobalt tetra-fluoroborate hexahydrate. Various Bronsted acid catalysts (10 - 20 mol%) were used to obtain the corresponding lactams in high yields at 80℃.展开更多
A production technique with the high yield and environmentally friendly process need be developed forε-Caprolactam(CPL)in the chemical industry.This technology is highly desired to design and synthesize high--perform...A production technique with the high yield and environmentally friendly process need be developed forε-Caprolactam(CPL)in the chemical industry.This technology is highly desired to design and synthesize high--performance catalysts for liquid phase Beckmann rearrangement of cyclohexanone oxime(CHO)to CPL.In this work,3-methyl-1-(propyl-4-sulfonyl)imidazolium methanesulfonate([PHSO_(3)MIM][MSA])with highly efficient and excellent yield is synthesized successfully.When the optimum molar ratio of ZnCl_(2)over[PHSO_(3)MIM][MSA]was 0.02,it exhibits the high selectivity(94%)of CPL at 90℃for 1 h.Interestingly,Fourier-transform infrared(FT-IR)investigations show that the functional Br∅nsted-Lewis acidic types of ionic liquids(ILs)are formed by the uniformly distributed ZnCl_(2)and[PHSO_(3)MIM][MSA].In addition,the hydrogen bond(H-bond)is formed between CHO and ILs.After ten reaction cycles,no significant structure changes are observed in the recovered[PHSO_(3)MIM][MSA]-ZnCl_(2).The solubilities of ILs are predicted by using COSMO-RS model,the results show that[PHSO_(3)MIM][MSA]is a promising candidate for the liquid phase Beckmann rearrangement of CHO into CPL.Finally,a theoretical model of the H-bond interactions between ILs and CHO is further confirmed to support the advance of reaction mechanism.A feasible way is provided for the CPL production technique in the liquid phase Beckmann rearrangement reaction.展开更多
基金the National Key Basic Research Development Plan“973”Project(No.2006CB202508)the National Key R&D Program of China(No.2021YFA1502600)+2 种基金State Key Laboratory of Catalytic Materials and Reaction Engineering(RIPP,SINOPEC)(No.33600000-20-ZC0607-0024)the SINOPEC Project(Nos.411058 and 413025)the National Natural Science Foundation(Nos.21808244,22178347,and 22072182).
文摘Developing efficient and stable zeolites for vapor-phase Beckmann rearrangement of cyclohexanone oxime is still a great challenge to realizeε-caprolactam(CPL)green production.In this work,the hierarchical porous silicalite-1 zeolites with multiple hollow structure(S-1-M)are explored by in-situ desilication−recrystallization post-treatment of spongy highway-like zeolites(S-1-S),which are synthesized through silanization synthesis of conventional bulky silicalite-1(S-1).Compared to S-1,S-1-M achieves superior catalytic performance,with improving the CPL selectivity from 85.7%to 94.1%and prolonging the catalyst lifetime from 74 to 126 h at a weight hourly space velocity(WHSV)of 6 h^(−1).Comprehensive physiochemical studies demonstrate that the highly dispersed intracrystalline cavities within S-1-M endow greater mass diffusion and better quasi acidity inducing by the enhanced H-bonds among abundant H-bonded silanols,which is cooperatively responsible for its superior catalytic performance.
文摘The addition of platinum over the B2O3/TiO2-ZrO2 remarkably enhanced its catalytic stability in the vapor phase Beckmann rearrangement of cyclohexanone oxime under the carder gas of H2. The content of coke deposited on catalyst surface was decreased from 1.92% over the B2O3/TiO2-ZrO2 to 1.14% over the platinum promoted B2O3/TiO2-ZrO2 after reaction of six hours. This result indicates that the platinum added on the B2O3/TiO2-ZrO2 catalyst plays an important role in reducing the coke formation on the catalyst surface.
基金support from the Natural Science Foundation of Gansu Province(No.3ZS061-A25-019)the Scientific Research fund of Gansu Provincial Education Department(No.0601-25)
文摘Under mild conditions, conversion of a variety of ketoximes and aldoximes to their corresponding amides and nitriles proceeded in the presence of PEG-SO3H with high yields.
基金Supported by the National Natural Science Foundation of China(Nos.20771030,20671025)
文摘Six Brnsted acidic ionic liquids（ILs） 1a―1f were synthesized and used as the dual solvent-catalyst systems for Beckmann rearrangement reactions. Among ILs 1a―1f, IL 1a exhibited the highest catalytic activity and successfully catalyzed the Beckmann rearrangement of ketoximes, and the corresponding amides were obtained in good to excellent yields（74%―92%）. In addition, IL 1a could be recovered easily and reused at least three times without any loss of catalytic activity.
文摘Deoxo 6 deoxy 6,9 epoxy 9,9 a didehydro 9 a aza 9 a homoerythromycin A (1), 9 deoxo 11 deoxy 9,11 epoxy 9,9 a didehydro 9 a aza 9 a homoerythromycin A (2) and 9 a aza 9 a homoerythromycin cyclic lactam (3) were synthesized by the Beckmann rearrangement of erythromycin A 9 (E) oxime (4). The structures of compounds (1), (2) and (3) have been identified by their spectral data. The reaction mechanism was also discussed. The yield of the Beckmann rearrangement of compounds (4) was better than that reported in literatures.
基金Project(20233040) supported by the National Natural Science Foundation of China and SI NOPEC
文摘Beckmann rearrangement mechanism of cyclohexanone oxime, based on the characteristic of self-catalyzed reaction and polymorphism was proposed. According to the suggested mechanism, the basic approach was the rearrangement of OXH+ while the SO3 acts as dehydrating agent and OXSO3 can turn to CPLSO3 ultimately. Considering self-catalyzed reaction between OXSO3 and CPLH+, kinetic model for Beckmann rearrangement was established. Corresponding parameters were estimated by using float genetic algorithm （GA） and simulation results agree well with the experimental data below -19.3℃. Industrial equipment was simulated and analyzed. Effects of key process parameters such as molar ratio of sulfuric acid to oxime and circulation ratio on the residual oxime are also discussed. The results show that the caprolactam exists as CPLH+ finally in oleum and the minimum molecular ratio of sulfuric acid to oxime can be 0.5 theoretically.
文摘The Beckmann rearrangement of cyclohexanone oxime was achieved by the combined use of cobalt salt and Lewis acids co-catalysts (each 10 mol%). Various combinations of cobalt salts and Lewis acids gave lactams in a satisfactory yield under mild conditions. This method makes it possible to reduce undesirable byproducts.
文摘Beckmann rearrangements of oximes to lactams often require harsh conditions and/or the use of large amounts of acid catalyst. To reduce the amount of Bronsted acid required, and to avoid the formation of a large amount of undesirable byproducts under mild reaction conditions, a low environmental load process was developed. Beckmann rearrangements of cyclohexanone oxime and cyclooctanone oxime were achieved using a combination of a Bronsted acid and cobalt tetra-fluoroborate hexahydrate. Various Bronsted acid catalysts (10 - 20 mol%) were used to obtain the corresponding lactams in high yields at 80℃.
基金financial support from the National Natural Science Foundation of China(grant numbers 21776300,21890763 and 22078355)Science and Technology Department of Qinghai Province(grant number 2022-GX-152)
文摘A production technique with the high yield and environmentally friendly process need be developed forε-Caprolactam(CPL)in the chemical industry.This technology is highly desired to design and synthesize high--performance catalysts for liquid phase Beckmann rearrangement of cyclohexanone oxime(CHO)to CPL.In this work,3-methyl-1-(propyl-4-sulfonyl)imidazolium methanesulfonate([PHSO_(3)MIM][MSA])with highly efficient and excellent yield is synthesized successfully.When the optimum molar ratio of ZnCl_(2)over[PHSO_(3)MIM][MSA]was 0.02,it exhibits the high selectivity(94%)of CPL at 90℃for 1 h.Interestingly,Fourier-transform infrared(FT-IR)investigations show that the functional Br∅nsted-Lewis acidic types of ionic liquids(ILs)are formed by the uniformly distributed ZnCl_(2)and[PHSO_(3)MIM][MSA].In addition,the hydrogen bond(H-bond)is formed between CHO and ILs.After ten reaction cycles,no significant structure changes are observed in the recovered[PHSO_(3)MIM][MSA]-ZnCl_(2).The solubilities of ILs are predicted by using COSMO-RS model,the results show that[PHSO_(3)MIM][MSA]is a promising candidate for the liquid phase Beckmann rearrangement of CHO into CPL.Finally,a theoretical model of the H-bond interactions between ILs and CHO is further confirmed to support the advance of reaction mechanism.A feasible way is provided for the CPL production technique in the liquid phase Beckmann rearrangement reaction.
